Bump Charge fully explained - we may have to deal with it

[bjanow]

In my experience with rugged devices in my full time job, devices require and continue to run off the battery because the battery can handle the current draw from the radios demanding power at a peak level. For example, the WAN and WLAN radios all of sudden are powering up or powering down, the current draw can be pretty huge. If running off of AC, the AC charger needs to be able to handle that draw. Except the AC chargers are meant to be made as cheap as possible.

An example would be installing a 1 Farad Capacitor between your Car Audio Amplifiers and the battery. Allowing the instant demand for power during the bass lines to come from CAP and not from the car battery or DC system. The phones battery can handle the instant demand for power.

I cannot explain whats happening in the Droid Inc. But if I had to bet money, I would bet its the same as I described above, which is what is happening for instance, in a motorola rugged mobile hand held.

Awesome evaluation - lots of work...

Always love to hear from Dustin. Always great analysis.

 

[sdrawkcab25]

Well the issue of bump charging in general hit phandroid:

http://phandroid.com/2010/12/25/you...is-lying-to-you-and-its-not-such-a-bad-thing/

 

[DustinF00]

Well the issue of bump charging in general hit phandroid:

Your Smartphone’s Battery Gauge is Lying to You (and it’s not such a bad thing) | Android Phone Fans

Right, we all kinda already knew that Bump Charging worked and that the devices weren't really staying at 100% charged when charged all night...

I've noticed that a fully charged battery can be anywhere from 3.9 to 4.0 volts and then a bump charge can get you anywhere from 4.1 to 4.15 (most common) and occasionally 4.2v...

So the post makes sense that the battery is running longer before its depleted and certainly longer than that of the non-bump charge phone.

In the end, I don't exactly see how bump charging depletes battery life considering batteries normally measure in charge cycles which I thought was measured from a certain % below 100% to being charged to 100%.

Either way, pushing more juice into a battery must be negative in some way - but its hard to be quantitative about how bad...

 

[Medion]

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In the end, I don't exactly see how bump charging depletes battery life considering batteries normally measure in charge cycles which I thought was measured from a certain % below 100% to being charged to 100%.

Battery life is measured in full charge cycles (which is "0% to 100%"). Anytime you charge/discharge a battery, you're doing a partial charge cycle.

The problem with the Incredible is that it seems that the battery is used to complete the circuit (IE, the phone won't even turn on without the battery inserted, even if the phone is plugged in). Now, there have been a few to say or suggest that they've seen or heard of Incredibles (and one person said he previously owned one) that would work without a battery inserted, but so far, no one has come forward with proof of their existence.

So, why is this method of use a bad thing? Simple. When you charge or discharge a battery, you're shortening it's overall life. When you charge a HTC Droid Incredible, you are simultaneously charging/discharging the battery due to poor design. That's not even counting the bump charge, which is essentially double-tapping the battery.

If you use the Incredible the way it was intended, your battery should last you the whole 2 year contract, though it obviously won't be as good at the end of the two years as it was when new. But if you're the kind of person who needs to bump charge and doesn't mind eventually replacing the battery, I have a better solution. Buy and external charger and a 2nd battery. Swap the batteries as needed. This gives the battery a complete charge without messing with a bump charge or draining the battery while charging. You'll have two batteries that easily last you the two years, as opposed to going through 3-4 batteries over the life of the phone.

And there's a guy here who continually spouts fud about external chargers overcharging the battery, no matter how many times I correct him. This doesn't happen. The battery has it's own "safety" built in. It won't overcharge.

 

[hashi]

I think this issue is a pretty big deal, not so much the bump-charge component rather that core issue itself, that the phone works perfectly normally if it's powered down.

Translated:: The phone is a decent battery charger when *no software* is involved.

I've had two droids, the original Droid 1 (Motorola), and a Droid Incredible. I'm guessing that the charging circuitry itself is close to the same in both phones. When off, they behave the same. When the D1 is on, it behaves still the same (so works off the battery), yet the Dinc, regardless of Kernel, ROM, or anything else behaves differently and sucks it's power from the battery with the charging cable in. (Yeah, I know nothing new, just recapping for myself since I am a relatively new HTC owner).

----- brief thoughts on this ----

• IF (big if), I'm guessing correctly, what I just said above might mean that there is a built-in "shunt" that is software controlled. It just, in response to some low-level command, shunts power usage when the phone is on to the battery rather than the DC (ac converted) cable.
• IF that is in any way, correct, then there may be a way to prevent it from occurring, depending upon how low-level this event occurs.
• IF I'm totally wrong, then the only (maybe) solution would be a circuitry based solution and well, how many are going to dive into their miniature circuit based phones with the proper gear to try to fix it if the fix was even known. It's also not so much we're fixing anything, we're just changing how it works.
• IF it's correct that it's a shunt, and we figure out where it is done, and undo it, then it just might be that we're still in trouble because of for example, the kernel's behavior. No guarantees on this stuff.

-- Things that make no sense to me but are being discussed in various other topics as if they are answers:

• Bump-charging, as if it's a fix to anything, and as if it's a 'fix' of some sort to a faulty kernel paradigm. That is way past the problem.

-- Where to start with this premise?

• I just downloaded (into my linux box) all the HTC kernel source for the DINC and will grep it to death for anything to do first for any #defines/(other code) that have to do with battery or charging, then if I'm lucky and get a hit, will try to figure out what else, other than charging paradigms is being done.
• I'd look at other things than the kernel (bootloader?) , but I'm not yet in possession of source for those, and aren't sure that is a possibility to even get them. I suppose people like those from "Unrevoked" have a notion, but I'll leave that for now.

Anyway: Sure, this is almost certainly an exercise in futility, but I have to admit that this is the most irritating thing about the Dinc for me. That top 5% of charge, from 95->100% when a battery is either taken from a regular charger or charged with the Dinc turned off, last the longest. It is non-linear, sort of like an old car's gas gauge so this seems worth some pursuit.

If you, (people like Medion) have already done all this and come up on empty, then please just reply and let me know. I have no need to reinvent the wheel or spin my own. Thanks -- hashi

PS: I read threads on this topic for about 2 hours before posting, but I mostly saw people addressing 'bump-charging' which isn't of any interest to me. I haven't yet seen someone try to address the cause so figured I'd at least take a look.


Edit:: Well:: Unforunately I thought I'd read a lot on this but mostly I missed a lot of important points, many right here in the thread. My apologies.

I read quite a few lines of semi-relevant source from kernel source, many from power_supply.h and many from battery.c and the various iterations of battery.c (*_battery.c). There are numerous references to a diode in the circuitry that is making the decision path clear without any software involvement. It appears the kernel has nothing to do with the part I was interested in. No big surprise. Now that I've reread and see that you can't run the Dinc without a battery inserted, none of my post is relevant.

The only thing now that would be entertaining, and only if I have a spare Dinc I can get ahold of (well, they'll be next to nothing to buy soon), would be to locate the charge circuitry, and see if there's some logical way to overcome the shunt. That means, perhaps changing/modifying the diode circuitry after figuring out which component(s) are needed to get away with this and get the effect of only using the battery when the battery is all there is available. That is way past what I really wanted to do, but perhaps still a possibility. If anyone has a non-working Dinc and would like to donate it to "science" , just let me know.

Thanks -- Hashi

 

[kev205]

my problem is a bit different...
I plug it on charge at night with an orange light on and in the morning it still shows orange light,
its not fully charging, i havent seen a green light for weeks.
all these started after i did the upgrade in the os.
any ideas of what it might be?